Version:           1.5.1 (using KDE 3.1.1)
Installed from:    SuSE
Compiler:          gcc version 3.3 20030226 (prerelease) (SuSE Linux)
OS:          Linux (i686) release 2.4.20-4GB

If you want to send a drawing per mail, there are currently 3 possibilities, all awkard:

1) Use ASCII-graphics (breaks on email viewers with variable font width and is very, very limited. It's also time consuming to create)
2) Try to explain the drawing with words
3)
- Fire up graphics application (for example gimp or kpaint)
- make drawing
- save as some file in some temporary directory
- click on "attachement" in kmail
- find the file saved earlier
- maybe later delete the no longer useful file
This is very awkard and often not worth the time when you just want to make a small drawing.

I think it would be a great idea to add an "add drawing" button to the toolbar which would start a simple pixel-based drawing program or kpart (kpaint would be more than enough, IMO) to create a drawing which is automatically attached to the email.
Everything should work automatically - if you close the drawing module, no silly questions should be asked (like "do you want to save the file?"), the drawing should just be attached.
The GIF-patent runs out in June 2003 and GIF would provide the best compression for typical drawings (few colors) in my experience, but PNG is probably also good enough for this task.

AFAIK there is currently no mail program with that functionality, so this could give kmail an edge over the others.
Also because all popular emailers can view graphics easily there would be no interoperability problems at all.

Thanks,